Systems are known in which a binary encoded label on or attached to an article is employed either to identify the article or to provide some other information such as price, or in the case of mail, routing information (zip code), and in which optical scanning equipment is employed to read the label.
The labels may have a circular design so that orientation between the article to which the label is attached and the scanning equipment is not a problem. In some labels the information is coded as radial bars in two different colors such as black and white to represent binary digits "one" and "zero" respectively. An inner circumferential band of timing marks identifies the position of each data bit to the scanning equipment. The machines needed to make printing dies for bulk printed labels of the type described are very costly. In other systems the labels are printed with concentric rings to represent the information. Dies for making such labels may be easily machined but providing timing information on the label presents a problem. In the prior art the timing information for fixed invariable rates of scanning is most typically achieved by providing special timing bands at spaced radii from the center which increases the diameter of the label by the total width of the timing bands. Although such systems present a problem if the size of the label is important, they are still limited by the fixed rate of scanning required.
The above-identified copending application, assigned commonly to the assignee of the present application, discloses a label of circular design having a unique code integral with the arrangement of annuli to provide synchronizing information of a substantially fixed rate scanner.